CVE-2025-48700

Synacor Zimbra Collaboration Suite (ZCS): Cross-site Scripting

As of , CVE-2025-48700 in Synacor Zimbra Collaboration Suite (ZCS) is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch soon.

Exploited
Yes: CISA listed it on 20 April 2026
US federal deadline
23 April 20263 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.02Higher than 76% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
Vendor advice: wiki.zimbra.comLinks below, from CISA's entry.

What CISA says to do

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

CISA's required action

What the flaw is

Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability that could allow attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information.

CISA's description

An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0 and 10.0 and 10.1. A Cross-Site Scripting (XSS) vulnerability in the Zimbra Classic UI allows attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information. This issue arises from insufficient sanitization of HTML content, specifically involving crafted tag structures and attribute values that include an @import directive and other script injection vectors. The vulnerability is triggered when a user views a crafted e-mail message in the Classic UI, requiring no additional user interaction.

The CVE record's description, from mitre

CVE published
23 June 2025
Assigned by
mitre
CVSS
6.1 Medium (CVSS 3.1, from CISA-ADP)
CWE-79
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CISA SSVC, exploitation
active
CISA SSVC, automatable
no
CISA SSVC, technical impact
partial

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

Zimbra Collaboration Suite (ZCS): other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2026-73570OS Command InjectionSynacor Zimbra Collaboration Suite (ZCS)Patch nowForensic triage required by CISA0.72
CVE-2019-9621Server-Side Request Forgery (SSRF)Synacor Zimbra Collaboration Suite (ZCS)Patch this weekMetasploit module; EPSS 0.81; verified Exploit-DB entry0.81
CVE-2019-9670Improper Restriction of XML External Entity ReferenceSynacor Zimbra Collaboration Suite (ZCS)Patch this weekMetasploit module; EPSS 0.99; verified Exploit-DB entry0.99
CVE-2022-41352Arbitrary File UploadSynacor Zimbra Collaboration Suite (ZCS)Patch this weekRansomware use; Metasploit module; EPSS 0.950.95
CVE-2022-27925Arbitrary File UploadSynacor Zimbra Collaboration Suite (ZCS)Patch this weekRansomware use; Metasploit module; EPSS 0.990.99
CVE-2022-37042Authentication BypassSynacor Zimbra Collaboration Suite (ZCS)Patch this weekRansomware use; Metasploit module; EPSS 0.920.92
CVE-2023-34192Cross-Site Scripting (XSS)Synacor Zimbra Collaboration Suite (ZCS)Patch this weekEPSS 0.770.77
CVE-2024-45519Command ExecutionSynacor Zimbra Collaboration Suite (ZCS)Patch this weekEPSS 0.990.99
CVE-2022-27924Command InjectionSynacor Zimbra Collaboration Suite (ZCS)Patch this weekRansomware use; EPSS 0.940.94
CVE-2018-6882Cross-Site Scripting (XSS)Synacor Zimbra Collaboration Suite (ZCS)Patch this weekRansomware use0.30

All 17 entries for Zimbra Collaboration Suite (ZCS)

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